JPS6034771Y2 - Suction silencer for turbocharger - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an intake silencer for an exhaust turbine supercharger.

In recent years, exhaust turbine superchargers (hereinafter referred to as superchargers) for diesel engines have been rotating at higher and higher speeds as engines have become more supercharged.
The trend is toward larger air volumes, which tends to increase the noise from superchargers.

On the other hand, recent social trends have placed emphasis on improving the working environment, and it has become necessary to significantly reduce the intake noise level of the supercharger in diesel engines.

However, most conventional intake silencers for turbochargers are designed with smooth air flow lines inside the silencer to reduce air intake resistance. , as shown in Fig. 1, the annular silencer body a and the trumpet-shaped body are cast products with felt c lined on the inside, and a partition tube d made of a steel plate with felt attached to both sides is placed between them to form the sound deadening part. The entire outer periphery is a cylindrical intake air filter e.

Outside air flows as shown by arrow A and is guided to the impeller f of the supercharger.

In conventional silencers configured in this way, the trajectory of the flow of outside air until it is sucked into the impeller of the supercharger is a gentle curve as shown by arrow A, so the noise generated by the supercharger is reduced. The problem is that the number of times the sound is reflected by the felt-covered sound deadening part is small, and the sound is emitted to the outside after only a slight attenuation.

The purpose of the present invention is to eliminate the drawbacks of the conventional suction silencer for a supercharger as described above.The main body of the silencer is provided with an overhang that reverses the flow of air, and the overhang has an inclination angle. At the same time, the tips are rounded, and the sound absorbing material is closely attached to the inside of the main body and the sub-main body to reduce changes in the cross-sectional area of the airflow passage surrounded by the sound absorbing material. Accordingly, it is an object of the present invention to provide a suction muffler for a supercharger that enhances the muffling effect while keeping the pressure loss of airflow small.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in FIGS. 2 and 3.

First, the embodiment shown in FIG. 2 will be described. An annular main body 1 is made of light alloy casting and has a tapered projecting portion 2 having an angle α with respect to the axis of the muffler. The portion 2a is rounded.

The inside of the main body 1 is closely filled with a sound absorbing material 4 such as glass wool, and covered with a perforated plate 5.

The sub-body 3 is made of light alloy casting and has a cylindrical center part 3a projecting inward from the muffler, and a skirt part 3b extending radially outward from the center part and having a tip bent inward.

A sound absorbing material 4 is closely attached to the side wall of the air passage inside the sub-body 3, and the attachment is covered with a perforated plate 5.

An opening on the outer periphery sandwiched between the main body 1 and the sub-main body 3 is equipped with a suction filter 6 that takes in air from the entire periphery.

Next, we will discuss the function of the silencer.

The air sucked through the suction filter 6 is guided by the tapered projecting portion 2 of the main body 1 and gathers at the W section, and then changes the flow direction and flows from the X section to the Y section.

The air flow path formed by the overhanging portion 2, the rounded R at its tip, and the perforated plate attached to the inside of the main body 1 and the sub-main body 3 reduces the expansion and contraction of the air flowing between them, and reduces the pressure. In order to reduce losses, the dimensions are determined so that changes in flow velocity are small.

There is no sharp bend from the Y part to the impeller inlet of the supercharger via the second part, and the air enters the impeller 7 as a substantially simple accelerated flow.

The noise generated by the rotation of the impeller 7 first starts from the second part Y.
However, the sound absorption material inside the main body 1 is thick, and the projecting part 2 of the main body 1 is concave at an angle α to the direction of noise propagation. As a result, sound is reflected and absorbed sufficiently, and the amount of attenuation in this area increases.

Next, in the inverted section from the Y section to the W section via the X section, the sound reduction effect due to bending is large, so the noise level in the W section is sufficiently low.

The sound that has reached the W section is reflected on the outer surface of the protruding portion 2 of the main body 1, and then passes through the suction filter 6 and radiates all around, but the radiated noise level is small because the sound has already been sufficiently muffled.

The embodiment shown in FIG. 3 shows a case where a sound-absorbing partition tube 9 is added inside for use in a large-sized supercharger.

The rest of the structure is the same as the embodiment shown in FIG.

Note that although the tip end 2a of the overhanging portion 2 is rounded, this is not limited to a perfect circular arc, and may be any shape that substantially reduces air resistance, such as a polygon.

With the above configuration, the present invention has the following advantages.

(1) The thickness of the sound absorbing material 4 attached closely to the inside of the main body 1 is thick, and the protruding portion 2 of the main body 1 is concave at an angle α with respect to the propagation direction of the noise generated by the impeller. Because of this, the reflection and absorption of sound is sufficiently covered and the sound silencing effect is great.

(2) By reversing the direction of the sound from the Y part to the W part via the X part, a great sound silencing effect can be obtained.

(3) The overhanging part 2 of the main body 1 and its tip roundness R
The air passages formed by the perforated plates attached to the inside of the main body 1 and the sub-main body 3 are shaped so that expansion and contraction of the air flow is unlikely to occur, and therefore pressure loss is small.

(4) Air is sucked in through the filter that opens all around the silencer, so the silencer can be made compact.
It can be installed as is in the swirl chamber 8 of the supercharger.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional suction silencer for a supercharger, FIG. 2 is a diagram showing an embodiment of the silencer according to the present invention, and FIG.
The figure shows a modified example of the same. 1... Main body, 2... Overhanging part, 3
...Sub-body, 4...Sound absorbing material, 6...
...Suction filter.

Claims (1)

[Scope of utility model registration request] The muffler has an annular main body having an overhanging part that is sloped toward the direction of noise propagation, a cylindrical center part that projects inward, and a skirt part that projects radially outward from the center part. a sub-body having an air flow path between the main body and the sub-body, the distal end of the overhang portion being substantially rounded, and each of the main body and the sub-body A suction silencer for a supercharger, which includes a sound absorbing material having a shape in which the air flow path has approximately the same cross-sectional area throughout the air flow path, and is attached directly to the inside in close contact with the sound absorbing material.